Nonwoven agricultural protective fabrics are used by growers to cover and protect crops, such as vegetables, turf, juvenile citrus trees, ornamental crops, and the like, from the environmental effects of frost, insects, and dessication. Such fabrics protect the crops from such elements during their growth. Nonwoven agricultural protective fabrics must be lightweight, air and water permeable, insulative, able to pass light, and strong enough to avoid tearing as a result of handling and exposure to wind.
The nonwoven protective fabrics of the prior art can balance a grower's requirements for frost protection, light transmission, air and water permeability, desiccation prevention, and strength in order to meet particular needs. The needs of a grower, however, may change during the course of a single growing season. During the early spring when the possibility of frost exists, it is advantageous to use a protective fabric with a high degree of insulation in order to protect young growing plants against freezing. Later in the season, once the risk of frost has ended, it is advantageous to use a protective fabric which has a higher degree of air and water permeability as well as a higher degree of light transmission to assist in the growing process. The goals of frost protection and growth enhancement by a protective fabric result in compromise between the need for insulation versus the need for air and water permeability and light transmission over the entire growing season.
A non-woven material is ideally suited for use as a row cover, which comprises a flexible, translucent covering that is installed over a row of plants to enhance growth and yield. Row covers are placed over the crop at the time of seeding or transplanting. Then, as the crop grows, the row cover is pushed upwardly without causing any damage to the crop.
The two most commonly used nonwovens for agricultural purposes are spunbonded polyester and polypropylene. Also, needlepunched nonwovens have become popular in a number of fields. For example, a relatively new needlepunched root wrap product promotes root growth. This may replace conventional burlap which is so often seen covering roots and associated soil for tree saplings.
A number of manufacturers make protective agricultural fabric. For example, manufactured and sold under the trademark Kimberly Farms is a spunbonded polypropylene fabric. Other agricultural protective fabrics include Linktuf agricultural film manufactured by the Dow Chemical Company, Midland, Mich. Linktuf film is a rib-reinforced low density polyethylene plastic. Other agricultural protective covers include spunbonded polyester manufactured by The Inter Tech Group, North Charleston, S.C., and sold under the trademark Reemay, and a nonwoven polypropylene fabric under the mark Seed Shield sold by Amoco Fabrics and Fiber Co.
In the recently published literature, it has been reported that Reemay spunbonded polyester fabric has been used by vegetable growers and home gardeners. It is lightweight and the plants grow freely underneath and push up the fabric as they grow. The Reemay fabric protects the plants from cold wind, scorching sunlight and insect damage.
As is well known, plants grow well if they are located within a greenhouse. A greenhouse typically provides relatively high humidity and temperatures higher than that outside the protective environment of the greenhouse. Although the hereinbefore described commercially available covers provide a balance between protection and transmission of air and water, none appear to provide a greenhouse effect in which moisture may be retained to aid in the crop's growth while protecting the crops from damage.
What is needed and what seemingly is not provided in the prior art is a horticultural fabric which provides conditions of relatively high humidity for growing crops. Desirably, the sought after horticultural fabric is lightweight and low enough in cost to have potentially attractive markets.